TNM 合金作为典型的 γ-TiAl 合金，密度较低且比强度高，在航空航天领域的服役潜力巨大，但其室温脆性较大且变形机制复杂，传统拉伸试验难以直观捕捉局部应变的演化规律，制约了其成形工艺优化与应用拓展，因此需要精准表征其变形行为的有效方法。 数字图像相关法(digital image correlation, DIC)作为一种新兴技术，具有测量范围广、

精度高、非接触等优点，可以直观显示合金在变形过程中的应变分布及位移演变情况，但鲜少用于研究 TNM 合金室温拉伸过程中的应变及位移变化。 基于此， 为直观显示 TNM 合金在室温拉伸过程中的应变及位移分布行为， 本文结合DIC 设备及其软件 Istra 4D 进行了研究。 结果表明，室温拉伸时，TNM 合金的真应力-应变曲线呈现弹性变形和加工硬化阶段，无屈服平台，抗拉强度为 464.35 MPa，断后伸长率为 3.39%；借助 DIC 技术捕捉了 TNM 合金拉伸过程中的应变分布及位移变化，发现试验制备散斑质量良好，位移随时间近似线性增长，前期波动较大，后期趋于平稳。 验证了 DIC在 TNM 合金拉伸变形过程中的适用性，该方法可实现从宏观到微观尺度的全场、非接触变形测量，揭示了传统方法无法观测的微观变形不均匀性、局部化现象及其与微观结构的关联，促进了多尺度、多物理场的原位耦合分析，为理解复杂的变形机制、损伤过程和验证先进材料模型提供了不可或缺的实验依据。

As a representative γ-TiAl alloy, the TNM alloy has a low density and high specific strength, demonstrating significant potential for application in the aerospace industry. However, its pronounced room-temperature brittleness and complex deformation mechanisms pose challenges for conventional tensile testing, which is limited in capturing the evolution of localized strain. This constraint hinders the optimization of its forming processes and broader application. Therefore, there is a pressing need for an effective and precise method to characterize its deformation behavior. Digital image correlation (DIC), an emerging technique, offers advantages such as a broad measurement range, high accuracy, and noncontact operation. This enables visualization of the strain distribution and displacement evolution during deformation.

Nevertheless, its application in studying strain and displacement variations in TNM alloys during room-temperature tensile testing remains limited. To address this gap and provide a clear depiction of the strain and displacement distribution behavior of the TNM alloy under room-temperature tension, this study employed DIC equipment and its associated software, Istra 4D. The results indicate that the true stress-strain curve of the TNM alloy during room-temperature tensile testing consists of elastic deformation and work hardening stages, without a distinct yield plateau. The ultimate tensile strength is measured as 464.35 MPa, with a postfracture elongation of 3.39% . Using DIC, the strain distribution and displacement changes during the tensile process are successfully captured. The quality of the speckle pattern used in the experiment is found to be satisfactory. The displacement exhibits an approximately linear increase over time, characterized by significant fluctuations in the early stages and a more stable trend in the later stages. This study confirms the applicability of the DIC method in analysing the tensile deformation behavior of TNM alloys. The DIC technique enables full-field, noncontact deformation measurements across macroscopic to microscopic scales, revealing deformation

inhomogeneities, localization phenomena, and their correlation with microstructural features that are not detectable via conventional methods. Furthermore, it facilitates in situ, multiscale, and multiphysical field coupled analysis, thereby providing essential experimental data for understanding complex deformation mechanisms and damage progression and for validating advanced material models.